Manage, tabulate, and estimate functions using variables and user-defined functions.
Sicyon calculator is all-in-one freeware tool for every scientist. The core of Sicyon is an VBScript/JScript scripter and the principal features are: estimate a function using variables and user-defined functions; matrix operations; plot/tabulate a function; find real roots, minimums, maximums and definite integral of a function; fit a function over data set; sophisticated units converter; database reader with various physical and chemical constants; and various tools as add-in applications.
Swiss-army knife kind of calculator, it has everything you would ever need from calculator. The fit module and matrix operations are very useful. The Unit conveter - for everyday use try Integrated env, the multi-tab one is more sophisticated but sometime too sophisticated.
Excellent universal calculator!
Cons
A few minor bugs do not spoil the excellent general impression.